CHEMISTRY SINCE TIME OF DALTON 



of coal, and yet again of a particle of sugar, of wood 

 fibre, of animal tissue, or of a gas in the atmosphere; 

 but from first to last from glass-cutting gem to in- 

 tangible gas there is no demonstrable change what- 

 ever in any single property of the atom itself. So far 

 as we know, its size, its weight, its capacity for vibra- 

 tion or rotation, and its inherent affinities, remain ab- 

 solutely unchanged throughout all these varying fort- 

 unes of position and association. And the same thing 

 is true of every atom of all of the seventy-odd ele- 

 mentary substances with which the modern chemist is 

 acquainted. Every one appears always to maintain 

 its unique integrity, gaining nothing and losing 

 nothing. 



All this being true, it would seem as if the position of 

 the Daltonian atom as a primordial bit of matter, inde- 

 structible and non-transmutable, had been put to the 

 test by the chemistry of our century, and not found 

 wanting. Since those early days of the century when 

 the electric battery performed its miracles and seem- 

 ingly reached its limitations in the hands of Davy, 

 many new elementary substances have been discovered, 

 but no single element has been displaced from its po- 

 sition as an undecomposable body. Rather have the 

 analyses of the chemist seemed to make it more and 

 more certain that all elementary atoms are in truth 

 what John Herschel called them, "manufactured ar- 

 ticles" -primordial, changeless, indestructible. 



And yet, oddly enough, it has chanced that hand in 

 hand with the experiments leading to such a goal have 

 gone other experiments and speculations of exactly the 

 opposite tenor. In each generation there have been 



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